Portable electronic devices, such as digital audio players, mobile telephones, and the like, have become increasingly popular. These devices generally require a user to hold the device to their ear either directly or indirectly by way of an earphone or a headset. Although these devices perform well for a single user, users sometimes find that amplifying the sound produced by these devices, for either multiple listeners or for “hands-free” use, is desired.
Radio transmitters may transmit audio signals from a device, such as a portable electronic device, to be detected by a remote radio receiver. In general, a transmitter is programmed to be switched between a few pre-determined channels, the user selecting one of the channels for transmitting the audio signals. The use of a transmitter usually requires a user to manually locate the available channels on a radio band to determine which channel is sufficiently quiet for transmitting the audio signals. The user generally determines which of the channels is quiet by listening directly to the quality of signals on the available channels. Once the user has identified a quiet spot, the user switches the transmitter to the selected channel and enables the electronic device. After starting up or enabling the electronic device, the device then transmits audio signals to the remote radio receiver.
For example, a user may use a transmitter in a digital audio player (e.g., an MP3 player) to wirelessly transmit music from the digital audio player over an identified quiet spot frequency to a car audio system, and may tune a receiver of the car audio system to the quiet spot frequency such that the car audio system receives and plays the music transmitted by the digital audio player.
In some cases, a quiet spot on a radio band becomes non-quiet due to, for example, movement of the device closer to a location of a transmitter of a radio station that broadcasts on the particular frequency of the selected quiet spot. For example, a user uses a transmitter in a digital audio player vehicle to transmit music over the selected quiet spot frequency, to be received and played by a car radio receiver. While driving, the music may be interrupted by a radio station broadcasting on the same frequency of the quiet spot. This may be due to the radio station's signal becoming stronger as the user drives closer to the source of the radio station's signal. Resultantly, the user has to repeat the process for finding another quiet spot. In some larger urban areas, the user may encounter extreme difficulties in locating and/or maintaining a quiet spot, due to large number of radio stations present in the urban area. In addition to the possible dangers of requiring the user to repeatedly locate quiet spots while driving, frustration may lead the user to forego use of the transmitter altogether.
The description in this section is related art, and does not necessarily include information disclosed under 37 C.F.R. 1.97 and 37 C.F.R. 1.98. Unless specifically denoted as prior art, it is not admitted that any description of related art is prior art.